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Master's Dissertation
DOI
10.11606/D.3.2017.tde-10102017-072924
Document
Author
Full name
Aldo Tonso
E-mail
Institute/School/College
Knowledge Area
Date of Defense
Published
São Paulo, 1994
Supervisor
Committee
Schmidell Netto, Willibaldo (President)
Facciotti, Maria Candida Reginato
Hokka, Carlos Osamu
Title in Portuguese
Estudo do processo descontinuo alimentado (Fed-Batch) para a síntese de glicoamilase por Aspergillus awamori NRRL3112.
Keywords in Portuguese
Amiloglicosidase
Batelada alimentada
Biorreator
Engenharia bioquímica
Engenharia de bioprocessos
Enzima
Fermentação (Bioprocessos)
Abstract in Portuguese
Utilizou-se um meio de cultivo a base de farinha de mandioca, suplementado com nutrientes, em fermentador agitado (700 rpm) e aerado (10 litros de ar/min), com volume de reação de 10 litros praticamente constante, fração de inóculo de 10% em volume, ph 4,0 e temperatura de 35ºC. Foram realizados ensaios com concentração total de açúcares de 20 g/l e 40 g/l, tanto descontínuos como descontínuos alimentados. Nestes variou-se a vazão mássica de alimentação (fs), o instante de início de alimentação e a condição do xarope de farinha (previamente hidrolisado ou não). Repetições dos ensaios descontínuos indicaram variabilidade de resultados elevada. Não se observou expressivas mudanças no crescimento microbiano, a não ser pelo aumento na velocidade específica nos ensaios descontínuos alimentados a 20 g/l. A síntese de glicoamilase foi sensivelmente aumentada nos ensaios descontínuos alimentados a 20 g/l (produtividade dobrada). A 40 g/l, obteve-se produtividade 26% superior. Os melhores resultados foram obtidos com fs=17,1 gart/h a so=20 g/l e fs=32,2 gart/h a 40 g/l, e obteve-se o pior no ensaio em que se alimentou desde o início de cultivo. A so=20 g/l a repressão se apresenta como principal mecanismo de controle de síntese de glicoamilase, não ocorrendo a mesma a 40 g/l, ensaios nos quais a indução tornou-se muito relevante.
Title in English
Fed-Batch process for the synthesis of glycoamylase by Aspergillus awamori NRRL 3112.
Keywords in English
Amyloglucosidase
Biochemical engineering
Bioprocess engineering
Bioreactor
Enzyme
Fermentation (Bioprocess)
Abstract in English
In order to study different processes and the influence of control mechanism on glucoamylase synthesis, several batch and fed-batch runs were made with Aspergillus awamori NRRL 3112. A medium containing cassava flour and nutrients were used in a 10 liters stirred and aerated tank, at pH 4,0 and temperature 35 °C. The batch and fed-batch runs used 20 and 40 g of total reducing sugars (TRS) per liter. In the fed-batch runs, the carbon source feed rate (fs), the feeding start time, and whether the syrup were pre-hydrolyzed or not were varied. Repeated batch runs showed significant variability. Notable changes in cell growth were not observed, unless by the increase of the specific growth rate in the 20 gTRS/l fed-batch runs. The enzyme productivity doubled in the lower sugar concentration fed-batch runs, but increased just 26% in the runs with 40g/l of TRS. The best results were achieved at 20g/l with carbon source feed rate=17,1 gTRS/h and fs=32,2 gTRS/h at 40g/l. The worst noted when the feeding started at the beginning of the run. At 20 gTRS/l, repression showed as the main mechanism control in order to synthesize glucoamylase. On the other hand induction became the relevant factor when 40gTRS/l were offered to microorganism.
 
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AldoTonso_D.pdf (7.73 Mbytes)
Publishing Date
2017-10-10
 
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